| Go supports [_anonymous functions_](http://en.wikipedia.org/wiki/Anonymous_function), which can form <a href="http://en.wikipedia.org/wiki/Closure_(computer_science)"><em>closures</em></a>. Anonymous functions are useful when you want to define a function inline without having to name it. | ||
package main |
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import "fmt" |
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| This function `intSeq` returns another function, which we define anonymously in the body of `intSeq`. The returned function _closes over_ the variable `i` to form a closure. | func intSeq() func() int { |
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i := 0 |
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return func() int { |
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i++ |
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return i |
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} |
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} |
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func main() { |
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| We call `intSeq`, assigning the result (a function) to `nextInt`. This function value captures its own `i` value, which will be updated each time we call `nextInt`. | nextInt := intSeq() |
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| See the effect of the closure by calling `nextInt` a few times. | fmt.Println(nextInt()) |
1 |
fmt.Println(nextInt()) |
2 |
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fmt.Println(nextInt()) |
3 |
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| To confirm that the state is unique to that particular function, create and test a new one. | newInts := intSeq() |
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fmt.Println(newInts()) |
1 |
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} |